This invention relates generally to passive thermal management of batteries and portions thereof, and more particularly to the use of microencapsulated phase change materials in conjunction with automotive battery packs, battery modules or individual battery cells as a way to improve thermal management of such battery components.
Lithium-ion batteries are being used in automotive applications as a way to supplement, in the case of hybrid electric vehicles (HEVs), or supplant, in the case of purely electric vehicles (EVs), conventional internal combustion engines (ICEs). In either variant, HEVs or PEVs belong to a larger class of vehicles known as electric vehicles (EVs). The high volumetric heat generation rate and generally passive construction of lithium-ion batteries provides both the durability and functionality needed to serve as a propulsion system for cars, trucks, buses, motorcycles and related automotive or vehicular platforms.
Temperature is one of the most significant factors impacting both the performance and life of a battery. Extremes (such as those encountered during protracted periods of inactivity in cold or hot environments, or due to extended periods of operation and concomitant heat generation on hot days) can negatively impact the ability of the battery to operate correctly, and in severe cases can destroy the battery entirely. Side effects of prolonged exposure to high temperature may include premature aging and accelerated capacity fade, both of which are undesirable. Conventional heat dissipation methods such as forced air and liquid cooling may prove to be effective at avoiding such side effects, but they add to overall vehicular system weight, complexity and parasitic power requirements.